A centralized Application Server (AS), when employed for a multi-participant service such as conference calling within a telecommunications system as illustrated in FIG. 4A, is generally not scalable and can be a bottleneck in system operation. Each Serving Call Session Control Function (S-CSCF) knows the address of the centralized AS and can send service requests directly to the AS. A centralized AS may reside in any Call Application Node (CAN) with an S-CSCF as shown in FIG. 4A, or in a dedicated node without an S-CSCF (not shown).
In a distributed Application Server architecture, an Application Server is co-located with an S-CSCF in every call application node and receives service requests from its local S-CSCF. Co-location of a plurality of multi-participant service application servers at each of a plurality of call application nodes as illustrated in FIG. 4B is scalable, but does not ensure that the service creator for a multi-participant service such as conference calling will receive requests relating to that service (e.g., requests to join the conference call) from other service users or participants since each S-CSCF only sends service requests to its local application server.
There is, therefore, a need in the art for an effective request routing mechanism for distributed multi-participant service application servers to ensure that participant service requests are properly routed.